1. Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the present invention relates to apparatus and methods for independently delivering a plurality of luminal prostheses within a body lumen, such as a blood vessel.
Coronary artery disease is the leading cause of death and morbidity in the United States and Western society. In particular, atherosclerosis in the coronary arteries can cause myocardial infarction, commonly referred to as a heart attack, which can be immediately fatal or, even if survived, can cause damage to the heart which can incapacitate the patient.
While coronary artery bypass surgery can be an effective treatment for stenosed arteries resulting from atherosclerosis or other causes, it is a highly invasive, costly procedure, which typically requires substantial hospital and recovery time. Percutaneous transluminal coronary angioplasty, commonly referred to as balloon angioplasty, is less invasive, less traumatic, and significantly less expensive than bypass surgery. Heretofore, however, balloon angioplasty has not been considered as effective a treatment as bypass surgery. The effectiveness of balloon angioplasty, however, has improved significantly with the introduction of stenting which involves the placement of a scaffold structure within the artery which has been treated by balloon angioplasty. The stent inhibits abrupt reclosure of the artery and has some benefit in inhibiting subsequent restenosis resulting from hyperplasia. Recently, experimental trials have demonstrated that the coating of stents using anti-proliferative drugs, such as paclitaxel, can significantly reduce the occurrence of hyperplasia in angioplasty treated coronary arteries which have been stented with the coated stents.
While the combination of balloon angioplasty with drug-coated stents holds great promise, significant challenges still remain. Of particular interest to the present invention, the treatment of extended or disseminated disease within an artery remains problematic. Most stents have a fixed length, typically in the range from 10 mm to 30 mm, and the placement of multiple stents to treat disease over a longer length requires the suggestive use of balloon stent delivery catheters. Moreover, it can be difficult to stent an angioplasty-treated region of a blood vessel with the optimum stent length.
For these reasons, it would be desirable to provide improved stents, stent delivery systems, stenting methods, and the like, for the treatment of patients having coronary artery disease, as well as other occlusive diseases of the vasculature. In particular, it would be desirable to provide stents, delivery systems, and methods for the treatment of disseminated and variable length stenotic regions within the vasculature. For example, it would be desirable to provide a practical method which permits a physician to optimize the length of the treated vessel which is stented according to the nature of the disease. More specifically, it would be desirable to provide apparatus, systems, and methods for facilitating the delivery of multiple stents and other prostheses to blood vessels or other target body lumens. Such apparatus, systems, and methods should be suitable for delivery of individual stents or prostheses having very short lengths, typically as short as 3 mm or shorter, at multiple contiguous and non-contiguous locations within a body lumen for optimized treatment thereof.
In addition, it would be desirable to provide stents, delivery systems, and methods for the treatment of disseminated and variable length stenotic regions within the vasculature. For example, it would be desirable to provide methods which permit a physician to optimize the length of the treated vessel which is stented according to the nature of the disease, either by adjusting the stent length in situ or by placing multiple stents of the same or different lengths over the treatment region. It would be further desirable to provide a practical method which permits a physician to deliver extended lengths of braided prostheses to blood vessels and other body lumens. At least some of these objectives will be met by the inventions described hereinafter.
2. Description of the Background Art
U.S. Pat. No. 6,258,117 B1 describes a stent having multiple sections connected by separable or frangible connecting regions. Optionally, the connecting regions are severed after the stent structure has been implanted in the blood vessel. U.S. Pat. Nos. 5,571,086; 5,776,141; and 6,143,016 describe an expandable sleeve for placement over a balloon catheter for the delivery of one or two stent structures to the vasculature. U.S. Pat. No. 5,697,948 describes a catheter for delivering stents covered by a sheath. U.S. Pat. No. 6,190,402B1, describes a self-forming vascular implant. U.S. Pat. No. 6,258,117, describes a multiple section stent structure; and U.S. Pat. No. 5,895,398, describes a clot retrieval device having a deployable helical clot snare. U.S. Pat. No. 5,755,772 describes a tubular prosthesis and method for its implantation by positioning the prosthesis at a target site, and everting an end session to lock the stent after expansion has been completed; and U.S. Pat. No. 5,769,882 describes conformable tubular prostheses and their placement in blood vessels.